Pollution, life satisfaction and health

Research in London, China, and Europe has shown that air pollution lowers people’s life satisfaction. In fact, a review in 2020 of 178 published papers showed that it lowers happiness and life satisfaction significantly, and increases anxiety, irritation, mental health issues, and even suicidal thoughts. But we don’t know whether the effect is more physiological than psychological. In other words: does pollution lower our life satisfaction on its own, or because it makes us ill?

Types and effects

The common air pollutants include:

• nitrogen dioxide
• sulphur dioxide
• PM10 (particulate matter with diameter 2.5-10 microns)
• PM2.5 (particulate matter with diameter of under 2.5 microns)

Atmospheric particulate matter, or particulates, are microscopic particles of solid or liquid matter suspended in the air. A micron, or micrometre (µm) is one thousandth of a millimetre.

They can all directly affect our health, causing:

• cardiovascular diseases
• respiratory diseases
• cancer
• low birth weight
• premature birth
• childhood respiratory diseases.

Air pollution can also damage the brain and nervous system, which can lead to mental health issues, psychotic episodes, cognitive impairments, anxiety, and depression. It can also affect life satisfaction directly because of the stress and anxiety of avoiding it – people may stay indoors instead of going outside, particularly if they can see pollution, or smell it.

Using the data

To understand the ways in which pollution affects us, I used 10 waves of Understanding Society, from 2009 to 2019, focusing on 59,492 people aged 16 and over. In each wave, study participants rate their overall life satisfaction on a scale of 1 (completely dissatisfied) to 7 (completely satisfied). I linked these answers to:

• air pollution data from the Department for Environment Food and Rural Affairs (DEFRA), which uses sources such as road traffic figures and data on industrial activities
• Lower Super Output Area data, which breaks the country down into areas with a population of at least 1,000 people – some of which, especially in urban areas, are smaller than one square kilometre.

This allowed me to match air pollution levels for each area in each year. I also used Understanding Society data on people’s self-rated health (a five-point scale from ‘excellent’ to ‘poor’), and took into account other factors which could influence the results, such as:

• age
• gender
• ethnicity
• financial situation
• whether they smoked.

Pollution linked to poorer health

I found that higher concentrations of nitrogen dioxide, sulphur dioxide, PM10, and PM2.5 pollutants were associated with poorer health, and poorer health was associated with lower life satisfaction. My mediation path analysis showed that almost half of the effect was mediated by health – that is, the pollution made people’s health worse, and this was what lowered their life satisfaction.

However, the different types of pollution didn’t all work in the same way. For sulphur dioxide, the indirect effect was much stronger – much more of the damage sulphur dioxide did to life satisfaction was through physical health, compared to the other pollutants. This may be because sulphur dioxide affects the lungs and can cause problems such as irritation, wheezing, coughing, and bronchitis. It can also damage neurons in the brain, resulting in degenerative diseases, and all these effects can contribute to poor health.

Sulphur dioxide mainly comes from heavy industry and burning fossil fuels for energy, while the other pollutants tend to come from exhaust fumes, so sulphur dioxide mainly affects people who live near factories and coal-fired power stations. They have worse respiratory and allergic symptoms and are at a higher risk of developing lung and uterine cancers. However, people who live in these areas may focus on positives, such as the employment and economic benefits of the industry, giving them better psychological health – reducing the direct effect of air pollution on their life satisfaction.

People in both industrial and non-industrial areas can smell and see traffic fumes, and the perception of pollution is a significant factor in its effect on life satisfaction. People who feel that their area is polluted in this way are more likely to experience stress and anxiety and to replace outdoor activities with indoor ones.

I also found that nitrogen dioxide (one of the pollutants from traffic) was more important in affecting life satisfaction in rural areas than urban ones. This may be because there is less traffic in these areas, so when people in the countryside are exposed to nitrogen dioxide, it has more effect on their life satisfaction than it would on someone in a town or city.

Taking the research further

I’d like to be able to look at postcode data, which focuses on smaller areas than the neighbourhood data in Understanding Society. It would also be good if future research could consider not just where people live, but where they work and whether and how they commute, too. Also, I used self-reported health data, and it would be interesting to see if objective measures such as hospital admissions would give a different picture.

Implications for policy

Nonetheless, this is the first research of its kind to look at the effect of pollution on life satisfaction and to consider the role of health – and to look at 11 years of data. Across the period I studied, air pollution fell – for all four types – showing that UK governments’ efforts to reduce emissions are working, but the results show that air pollution still affects our lives, and via different pathways.

We can use this knowledge to work out further ways of reducing pollution to benefit our health and wellbeing. The research also emphasises how important it is that policies which aim to improve life satisfaction should consider air quality and include plans to improve health.

Read the original research

Authors

Findings and impactHealth and wellbeing